Electric steam generator



Feb. 24, 1925. 1,527,761 H. L. UNLAND ELECTRIC STEAM eanmi'bn,

Filed Dec. 16, 1922 /9 A vIIYCM Inventor: Harry L Unland.

His Attorney;

Patented Feb. 24,1925.

UNITED STAT s PATENT. OFFICE.

HARRY L. UNI-AND, or scnnnncrnnrnnw Yoizx, ASSIGNOR r GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

' ELECTRIC STEAM GEhlERATOR.

Application filed December 16, 1922. Serial No. 607,267.

T0 aZZ whom it may concern: a

' Be it known that I, HARRY L. UNLAND, a citizen'.'of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Steam Generators, of which the following is a specification.

The presentinvention relates to steam generators or boilers of the electrode type wherein steam is generated by passing alternating current through Water, and has for its object to provide an improved regulating means for such generators. For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and claims appended thereto. a

In the drawing the figure is a diagrammatic view partly in section of a steam generator provided with a regulating means embodying my invention.

Referring to the drawing, 5 indicates the shell of an electric generator or boiler and 6 the electrodes which project into the shell through suitable insulators: 7. The elec-J trodes maybe connected to any suitable source oi alternating current, In the present instance three electrodes are shown "which adapts the generator or boiler for connection to a three-phase alternating current. Atthe bottom of the shell is a sump 8 provided with a blow-off valve 9, and also if desired, with an extraction valve 10 for drawing ofi' hot water. This arrangement of steam generator on boiler is shown only by way of example and is to be taken as.

typical of any suitable generator structure.

At 11 is indicated consumption means for 353 steam being conveyed to it by a pipe 12 and condensate being conveyed from'it back to the generator by conduit 13. This forms a closed system. v e

Now, according to my invention, T provide a storage and regulating tank 14 located a desired distance above shell 5 and connect it to the generator at a point below the water level at which the electrodes justtouch thewater. In the present instance tank 1% is shown as being connected to the boiler shell by a pipe 15, which connects to conduit 18. in a generator of this type the power input will vary with the extent to which the electrodes are submergedi. e. with the steam, such as for example, a heating 'coil,

level of the .water in shell 5. The water level A indicated in the drawing may be taken to indicate fullload \vater'level'and the water level B, no load water level. These are the operating limits of the waterv level in the generator. Tank 14 has a capacit-y slightly greater-than that represented by the volume of shell 5 between the full load and no load levels and is placed at a level above shell 5 to give a desired pressure head for i the generator. With full load water level 'A in shell 5 the water level in tank 14 is at A and with no load water level B in shell 5 the water-level in tank 14- is at B. I

With full load water" level A in the generator the pressure in the generator will be equal to the head represented by the distance between levels A and A. If the steam pressure increases above said value thewater level in shell 5 will be forced downward due to the increased pressure .and the water level in tank 14 will be raised. The lowering of the water level in shell 5 decreases the amount which the electrodes are submerged and hence the input of the generator. The maximum pressure which can occur in the generator is one equal to I the head represented by the difference in level between B and B. By giving tank 14 a suitable shape and a capacity slightly greater than the capacity of shell 5 between levels A and B, and by placing it at a suitable heightabove casing 5 the system can be made to give any desired value of maxi mum pressure within reasonable limits. I

At 16 is a suitable air reliei valve-to be used to let the air out of the system when starting. For ordinary low pressure operation the upper end of tank 14:is open to atmosphere through a valve 17. If it is de sired to employ a maximum pressure in the steam generator greater than that which can be obtained economically by the use of a. water column, I may accomplish this by providing on the storage tank a springloaded or safety type valve which will only open after a certain maximum pressure in tank '14 isfreached. In the present instance I have indicated such a valve at 18. it may be or any suitable type and is preferably adjustable' so it may be made to open at any desired pressure. To put valve 18 into service it is only necessary to close valve 1?.

{Connected to tank 14 is a feed water conduit 19 provided with a valve 20, which is used to supply make-up water to the system.

My invention is particularly well adapted for use with closed steam systems wherein the steam after condensation is returned to the generator, and in the drawing such a system is illustrated. The use of my in vention results in a very simple regulating means requiring no moving parts or special controlling or governing -means. At the same time it is reliable'in operation.

- While I have specifically described my invention as used. to. generate steam from water, this being the ordinary application, itwill of-course be understood that it may be used to generate vapor from any liquid desired.

Inaccordance with the provisions of the patent statutesl have described the principle of operation of mv invention, togetherwith the" apparatus which I now consider to represent the best embodiment thereof,

but I desireoto have it understood that the apparatusv-shownis only illustrative and that the invention may be carriedout by other means. I

What I claim as new and. desire to secure by Letters Patent of the United States, is

l. Thecombination with a vapor generator of the electrode type wherein vapor is generated by the passage of electric current between electrodes and theinput-isregu-' lated by varying the depth to which the electrodes are submerged, of means wherebysuch depth .is'varied in accordance with the pressure in the generator, said means comprising a storage tank located above from-the tank. y

8. In an electric boiler of the electrode the generator and 'a-conduit connecting} it to the generator below the liquid leveltherein.

2. The combination with a vapor generator of the electrode typewherein vapor is generated by the passage of electric current submerged will be varied to regulate the generatorby the passage of liquid to and type wherein vapor is generated by the passage of electric current between electrodes and the input is regulated by varying the depth to which the electrodes are submerged,

the combination of a boiler shell, electrodes depending into it, a closed circulating system having one side connected to the shell abo'vethe liquid level therein and the other side connected to the lower end of the shell,

a tank located above the shell, and a conduit connecting it to the .shell below the liquid level in the shell whereby when the pressure generated in the boiler increases liquid may be forced from the shell into the tank to-vary the depth to which the electrodes are submerged.

In witness whereof, I have hereunto setmy hand this 14th day of-December, 1922. I 

